Electrical connecter



1937 E. H. GREIBACH ELECTRICAL: CONNECTER Filed Sept. 1, 1934 INVENTOR.

5-H. G/E/BACH .3 W ATTORNEY Patented Feb. 9, 1937 UNITED smTEs PATENT OFFICE Emil Henry Greibach, Brooklyn, N. to Sonotone Corporation, New

Y., assignor York, N. Y., a

corporation of New York Application September 1, 1934, Serial No. 742,413

Claims. (01. 173-3323 I the terminals of the transmitter unit l2 a bat- This application is a continuation in 'part of my copending applications 'Serial No. 556,158 filed August 10, 1931 and Serial No. 701,878 filed December 11, 1933.

This invention relates to electric cord connecters and it is particularly concerned with cord connectors for hearing-aid. devices and like instruments in which electrical elements are dc:- tachably interconnected by means of flexible cords provided at their ends with connecters for establishing readily detachable, reliable, me

ch'anical and electrical connections between the ends of the cord and the device which they interconnect. 7

The foregoing arid other objects of the invention will be best. understood from the following description of exemplifications thereof, reference being had to the accompanying drawing wherein Fig. lis a diagrammatic view of an assembled hearing-aid device embodying the invention;

Fig. 2 is a perspective view of the complete three-prong cord-plug connection to the ampli- 1 tier of the'device;

Fig. 3 is a perspective View or the elements of the cordplug casing;

Figs. 3a and 3b are perspective views of the anchor member and the plug pins;

Fig. 4 is a horizontal sectional view through the cord plug along line 6-4 of Fig. 5;

Fig. 5 is a vertical sectional view of the cord plug along line 5- 5 of Fig. 6;

Fig. 6 is a vertical sectional view of the cord plug along line 6-6 of Fig. 5;

= with athree-prong plug. 19 detachably engaging.

Fig. 7 is an elevational view'oi the, detachable cord pin terminal for connecting the cord to the receiver terminals of the device;

Fig. 8 is a transverse'sectionai view through the receiver casing showing the detachable engagement of the cord pin terminal with the terminal sleeve of the receiver;

Figs. 9 and 10 are detailed views illustrating successive stepsin preparing the end of a cord strand for mounting in a pin terminal;

Fig. 11 is a view of the clipplate'before it is clamped over the end of a cord strand;

Fig. '12 isa view of the end of a cord strand in completed position before mounting in the pin terminal; and I Figs. 13 and 1 1 are a sectional and elevational view of a modified form of. cord-plug pin terminal.

In Fig. 1 is shown 'a hearing-aid device com-- prising a hearing imparting unitin the form ,of a telephone receiver l 0 having an actuating winding H, a microphone transmitter unit l2 with a control unit It, a battery It and an amplifier IS with two plug pins It engaging battery teminal sleeves ll, the several elements being interconnected by a cord l8 having a transmitter branch tery branch with a three-prong plug 2| for interchangeably engaging either the amplifier terminals 22 or the battery terminal sleeves l1, and a receiver branch 24 having two loose strand ends 25 provided with plug pin terminals 26 de-- tachably engaging terminal sleeves of the receiver III to which the receiver winding H is connected.

To secure full utility of the hearing-aid devices, it is not only necessary that the individual parts which participate in the electromagnetic and mechanical actions shall be eflicient and satisfactory, but it is also important that the cords and the connecting elements shall be as simple and small as possible but nevertheless be capable of withstanding the continuous handling and permit easy attachment and detachment of the cord ends to the elements of the device. In connection with an amplifying hearing-aid device as shown inFig. 1, where the connecting cord has several plug pins in the individual branches, I

' have devised a novel construction for the plugs,

larged on the drawing; the casing is preferably made of an insulating material, such as molded phenolic condensate, and has formed in its interior a large chamber HI extending through the full thickness of the casing being bounded on one side by the rear wall H2 and having opening H3 at the other side, which opening is of the full width and height of the chamber Ill. Into this chamber is inserted through the opening H3 an insert lit, the front portion of which fits the opening H3 and forms a cover enclosing the chamber. This insert ll l has also a rectangular block H5 projecting inwardly for the full thickness of the chamber so that its inner wall abuts'against the inner side of the 1 rear wall H2. Thus, when the insert is set into the chamber, it fills it up and fits firmly therein, its sides resting against the walls of the chamber. The projecting block H5 is of less height than the. front wall of the insert 4, leaving a free space in the top of the chamber bounded on one side by the rear. wall N2 of the casing and-on the other side by the front cover portion of the insert ll 4. In the center of the top wall of the casing is provided a perforation 6 for inserting cord strands Ill of a cord branch, ior.

ill

instance, branch 8d of Fig. l. The block; M5 is provided with three longitudinal square holes l2! which merge near the bottom into cylindrical portions E22 of a diameter equal to the width of the square. Into these square holes are in serted anchoringsleeves 023 as shown in. Fig. So having a central square portion i2 3 and a down ward cylindrical portion i225 fitting the square portion 112i and the cylindrical portion 822 of the insert holes, the upper portion lES of the sleeve being likewise cylindrical like portion and having near its end a groove it?! cut over a small portion along its periphery. The lower half of the sleeve is threaded, and the upper half of the sleeve forms a longitudinal cavity in which the ends of the strands li'l are clamped to secure a good mechanical connection between the sleeve and the strand, and also a good electrical connection between the sleeve and the conducting cord of the strand. The strand used for the cords of these devices are specially so as to be flexible and yet strong. The usual strands are composed of a core consisting oz? three or more intertwisted flexible conductors made by winding thin copper filaments over a thread so as to have the required conductivity and yet retain great strength. This core has wound thereon additional layers of flexible insulating material, such as silk, and is enclosed by a cover consisting, for instance, of suitably woven sillr threads so as to thoroughly protect the conducting core in the interior and at same time carry the strain imposed on the strands in use by pulling it, etc.

To mount. the strand end in the plug, the insulating, cover of the strand is removed of a portion of its length near the end, as shown in Fig. 9, and this exposed core portion is then folded over the cover portion next to it as shown in Fig. 10. Then a little sheet metal plate its, shown in Fig. 11, having punched on its surface a few holes so as to provide projecting ridges adapted to grip the strand cover is clamped The clipped strand ends ill are then inserted into the hollow chamber of the sleeve B26 and clamped within the sleeve by compressing the upper end of the sleeve above the groove 62! so that the strand end is firmly locked in the sleeve and it cannot get out therefrom. A good electrical and mechanical connection between the strand and the anchor sleeve lid is thus ob- ,tained, the anchor sleeve being of metal, such as brass.

After the strandends have thus been secured within the anchor sleeves, the anchor sleeves are pushed into the square holes lZl of the insert block H5 and the insert i2 5 is inserted into the casing chamber in the way shown in Fig. 8. The

underside of the plug has atthree points opposite the' threaded openings 1% of the sleeves, three openings H33 of the'same diameter, with a, slightly enlarged recess on the undersurface aovucoo of the plug arranged to receive the plug pins H36, having a shoulder H5 adapted to fit the recess and a threaded shanlg portion ltll adepted to be screwed in and to engage the threaded portion lid of the sleeve.

The plug pin terminals 26 mounted on theends of loose strands as used, for instance, to connect the receiver strands 25 to the receiver winding M are likewise of special construction to secure a good conducting connection between the plugs and the conducting core of the stran and at the same time also secure a good me chanical connection and prevent pulling out of the strands from the plugs. Each. plug pin has atone end a portion 2i shaped to engage the cooperating socket terminal and may inshape as shown in Figs. 7, l3 and 14. interior of the plug pin is hollow and forms a longitudinal cavity 28 open at. the end. Into this cavity 223 is inserted the end of the cord strand, after being first prepared as shown in Figs. 9 to 12 and described before.

Eefore securing the clip on the strand end, collar as shown in Figs. 7 and 3, is first slippe on the strand end so that when the clip is mounted the collar slides freely back of it. The end with the clip mounted thereon is then slipped into the cavity 28 of the plug pin 26. With the clip placed inside, the portion of the pin walls The near the opening is compressed or clamped tov gether so as to firmly lock the clip strand end the cavity and to prevent its being pulled out of it. 'Ereierably, the end portion 01' the pin its end has a small cut 33 along a portion oi periphery so that the portion near the end oi the mounting of the plug on the strand end thus com- 1;;

pleted. The finished unit is extremely simple manufacture, gives an excellent conducting con nection between the conducting core of the and the plug pin, provides a strong positive me chanical connection between the plug pin the cord strand, and has a pleasing neat app-eon ance.

The features of the invention described above are susceptible of many modifications that will suggest themselves to those skilled in the art.

I claim: I

"i. In a detachable terminal connection of cord for an electric instrument subject to handling comprising, in combination with. the terminal end of a flexible cord strand having a flexible insulating cover and a flexible conducting core having an exposed end portion folded over the exterior of said cover, an elongated solid conducting plug member having an exposed contact portion on its outward end and a longitudinal deformed cavity at its inward end surrounding and compressing the strand terminal end, and a cover enclosing the inward end of said plug member end and a longitudinal deformed cavity at its inward end surrounding and compressing the strand terminal end, and a cover enclosing the inward end of said plug member and the adjoining portion of said strand. j

3. In a detachable terminal connection of a cord for an electric instrument subject'to handling comprising, in combination with the terminal end of a flexible cord strand having a flexible insulating cover and a fiexible conducting core having an exposed end portion folded over the exterior of said cover, a longitudinally extending plug casing of insulating material having a hollow chamber with an opening on one side thereof, an inward Wall having a strand opening,

and an outward wall having a terminal opening, said strand terminal end extending through said strand opening into said chamber, an insert of insulating material having an external wall enclosing said chamber-opening to complement the exterior of said casing and a block extending into the interior of said chamber having a perforation aligned with said terminal opening, a conducting anchor member slidably fitting into said perforation and locked therein against rotation and movement in outward direction, the inward end, of said anchor member having a longitudinal cavity surrounding andholding grippingly clamped the strand terminal end, and an elongated plug terminal member having an exposed outward contact portion and an inward portion for detachable locking engagement with the outward end of said anchor member through said terminal opening for locking said insertin said casing, said anchor member and the connection thereof with said strand and said terminal memberbeing entirely enclosed by said casing.

4. In a detachable terminal connection of a cord for an electric-instrument subject to handling comprising, in combination with the terminal end of a flexible cord strand having a flexible insulating cover and a flexible conducting core having' an exposed end portion folded overthe exterior of said cover, a clip of relatively soft sheet metal clamped around said folded strand terminal end and gripping said cover and folded core, a longitudinally extending plug casing of insulating material having a hollow chamber with an opening on one side thereof, an inward wall having a strand opening, and an outward wall having a terminal opening, saidstrand'terminal end ex tending through said strand opening into said chamber, an insert of insulating material having an external wall enclosing said chamber opening to complement the exterior of said casing and a block extending into the interior of said chamber having a perforation aligned with said terminal opening, a conducting anchor member slidably fitting into said perforation and locked therein against rotation and movement in outward direc-' tion, the inward end of said anchor member having a longitudinal cavity surrounding and holding grippingly clamped the strand terminal end, and

an elongated plug terminal member having an exposed outward contact portion and an inward portion for detachable locking engagement with the outward end of said anchor member through said terminal opening for locking said insert in said casing, said anchor member and-the connection thereof with said strand and said terminal member being entirely enclosed by said casing.

5. In a detachable terminal connection of a cord for an electric instrument subject to handling comprising, in combination with terminal ends of two or more flexible cord strands, each having a flexible insulating cover, and a flexible conducting core having an exposed end portion folded over the exterior of said cover, a longitudinally extending plug casing of insulating material havinga hollow chamber with an opening on one side thereof, an inward wall having a str'and opening, and an outward wall having two terminal openings, said strand terminal ends extending through said strand opening into said chamber, an insert of insulating material having an external wall enclosing saidchamber opening to complement the exterior ofsaid casing and a 'block extending into the interior of said chamber having perforations aligned with said terminal openings, conducting anchor members slidably fitting into said perforations and looked therein against rotation and movement in outward direction,- the inward ends of said anchor 1 members having longitudinal cavities surround-- ing and holding grippingly clamped said strand terminal ends, and elongated plug terminal members having exposed outward contact portions and inward portions for detachable locking engagement with the outward ends'of said anchor members through said terminal openings for locking said insert in said casing, said anchor members andthe connection. thereof with said strands and said terminal members being entirely enclosed by said casing 6. In a detachable terminal connection of a cord for an electric instrument subject to handling comprising, in combination with terminal ends of two or' more flexible cord strands, each having a flexible insulating cover, and a flexible conducting core having an exposed end portion ing to complement the exterior of said casing and a block extending into the interior of said chamber having perforations aligned with said terminal openings, conducting anchor members -slidably fitting into said perforations and locked therein against rotation and movement in outward direction, the inward ends of said anchor members having longitudinalcavities surrounding and holding grippingly clamped said strand terminal ends, and elongated plug terminal members having exposed outward contact portions and inward portions for detachable locking engagement with the outward ends of said anchor members through said terminal openings for locking said insert in said casing, said anchor members and the connection thereof with said strands and said terminal members being entirely enclosed by said casing.

E. H. GREIBACH. 

